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Brighten old, dark pennies in seconds! No scrubbing necessary at all. The effect is achieved only where the mixture has been in contact with the coin, so ensure you cover the entire coin!

Steps

1

In a small container, place a small amount of table-salt (1 gram is plenty).[1]

2

Add enough acetic acid (vinegar, white vinegar is most recommended) to moisten the salt into a paste.[2]

3

Now simply apply the paste to the penny wherever you want it to brighten up. The effect is immediate and obvious.[3]

4

Note: if you don't have any vinegar you can substitute it with tomato ketchup because it is also acidic. This works well for copper bottom pans too![4]

Community Q&A

Since all alcohol is neutral (having neither acidic or alkaline charges) it will only remove ceraint oil base soils. The advantage is it will not cause any decrease in numismatic value, but there are better options for cleaning materials.

What are ultrasonic cleaners when it comes to cleaning copper coins? Do I need to add liquid to it?

Denny Hipsher

Community Answer

Ultrasonic cleaners work by microcavitation. Or in layman's terms, by generating microscopic bubbles between a hard surface and a softer material, and allowing them to catastrophically collapse. This process only works in fluid. So at the very least you need distilled water as a working medium. As for what is best to add and enhance the cleaning action, I'm not sure. Caution: blood plasma counts as a fluid. So if you leave your hand in the ultrasonic cleaner long enough, it will "clean" the flesh from your bones. This is usually only a concern for industrial levels of exposure.

Tips

Because the effect is achieved only where the mixture has been in contact with the coin, this allows one to get creative with the contrasting features of the coin itself with your choice of different colored copper. For instance, use a small applicator to "paint" only the heads for an unusual "cameo" effect.

If it's a very thin coin, don't clean it as the vinegar can scorch through it.

Do not leave the coin in the ketchup for more than an hour or two as it will leave a green oxidation on the coin.

Warnings

Do not ever use this solution on valuable coins. Although a vinegar solution is a weak of acetic acid, it could result in the creation of undesirable tones or lustre, or the destruction of the patina. Leave it for a collector to assess and deal with. You may cause irreparable damage. The same goes for all antiques -don't clean, paint or polish anything that may have value before getting them appraised.

Different types of coins require different cleaning solutions, so ask an expert if you are not sure.

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wikiHow is a “wiki,” similar to Wikipedia, which means that many of our articles are co-written by multiple authors. To create this article, 47 people, some anonymous, worked to edit and improve it over time. This article has also been viewed 372,142 times.